The WordPress File Monitor Plus plugin monitors all the files in your WordPress site. If any files change, are added or removed you will receive an email detailing the changes.
Why You Should Use WordPress File Monitor Plus
Monitoring your site is a crucial part of having a sound security strategy against hackers and spammers. What this plugin does is monitor all the files in your WordPress-powered website. Someone who is attempting to break into your site is not doing so in order to help you out. They are going to do some damage and leave you and your site in their wake.
One thing that hackers will most likely do is add files to your website. These files essentially lay the groundwork by allowing someone to execute files from their own servers. These files can do all kinds of nasty stuff like place links and ads on your site and even hijack your traffic. It’s bad news!
Update: This plugin is no longer available. However, there are some great solutions out there that will do what Monitor Plus did plus a whole lot more. Check out All in One WP Security